The port zone are essentials to the socioeconomic development of the Amazon region,
however, it can contributes to disturbing aquatic ecosystems by the intensive shipment drive
and occasional discharge of pollutants. Among the chemical species that are harmful to the
environment and associated with the port activities stand out the heavy metals and petroleum
derivatives. Such xenobiotic molecules induces genotoxic damages to aquatic biota. The
present study aims to investigate the possible genotoxic effects in fishes Pimelodus blochii
and Geophagus proximus in situ exposed to aquatic pollutants in the port zones of Santarém
and Itaituba cities, situated in the Tapajós Rivers, western Pará State. Therefore were
collected 60 fishes, G. proximus (n=39) and P. blochii (n=21) from the both localities. The
micronucleus test and counts of erithrocyte nuclear abnormalities were adopted for detection
of genetic material losses and nuclear membrane lesions, while the comet assays was applied
to evaluate DNA damages. P. blochii from the Itaituba port zone showed larger index of
damage to DNA, while G. proximus from Santarém showed greater frequencies of
micronucleus and nuclear abnormalities. A comparison between both species revealed that G.
proximus is more susceptible to the xenobiotics found in the study area. The last increasing in
the port sector in the Tapajós system may be associated with the high level of genotoxic
damages observed in fishes from the Santarém area. On the other hand, the prolonged
exposition to mining residuals and urban garbage could explain the high level of DNA
damage observed in P. blochii from the Itaituba area. Biomonitoring and studies of water
quality are recommended in view of the projections pointing to the growth of port sector in
the western Pará State.
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